Here is a picture of the MAF conversion in my car. Note that the cone filter probably sucks in all sorts of hot air and fan wash because it is not shielded from such things. Mike, of Green Hornet fame (if you've seen his car you would understand) has a very nice heat shield setup in his car. His fabricator is willing to duplicate it if anyone wants one.
I like the fact that there is weatherstipping between the shield and the hood to keep all the hot stuff out. Mike also went to the trouble of applying some insulating material to both sides os the shield.